WagonmasterRuss

iTrader: (2)

Hi All,
I installed EBL a while back. I got it mostly OK and never really went too far with it. It never has felt perfect but it was OK. I just had my first tailpipe test with the computer in and failed for hydrocarbons
Please take a look at this for me an point me in the right direction
FYI, the engine is basically stock TBI with headers and a heated O2 sensor (see my sig).

Looks like my zipped file is too big to upload........... I can emeil the DAT file to anyone interested.

Thanks

klause83z28

PM sent.

ASE doc

HC, or hydrocarbon is petroleum distillate, or motor fuel. HC exhaust emmisions are unburned fuel. It is caused by misfire. The best running engines produce a small amount of hydrocarbon exhaust emmisions and rely on several items to process these HC emmisions from the exhaust. The first item in this chain is the exhaust manifold. On a hot engine, manifold temp is high enough to burn the HCs as they leave the cylinder head. One thing that can help in this function is having timing set correctly. Too much timing lead at idle can cause the manifolds to run cool and limit their ability to burn off the HC. The next item in the chain is the catalytic converter. It is designed to process, or reoxydize the HC as well as CO. The three way cat also reduces NOx, another noxious gas that is regulated by the EPA. A major item on factory emmision controlled vehicles for the reduction of HC emmisions is the AIR or air injection reaction system. The "smog pump" as it's often known, injects fresh, oxygen rich, air into the cold exhaust manifold during engine warm up to engourage burning of HC and to speed the heating of the manifolds. Once the engine reaches design temp, the injected air is switched to the catalytic converter where it helps in oxydization of HC and CO.

So, since your HC failure was at idle only, I would start by pulling 2-4 degrees of idle timing. If you are using computer controlled timing, you should be able to set base timing wherever you need to and still create your desired timing curve. Of course be sure that you engine's runnability is good. Any misfire will cause increased HC emmissions. Be sure that, if so equipped, your AIR system is is proper working order. Once you have addressed engine idle and timing, AIR system function, and are still unable to acheive HC limits, replace your catalytic converter.

boldguy

you're almost there. I have found that if you run guaranteed to pass through the tank and when you go to re test, drive around for like 45 minutes at medium load, get the cats super hot, you will most likely pass. ive used gtp when i was on the border. If you were at like 1200 hc's id say pay the guy to pass you.